As for your question personally I wouldn't look through the viewfinder without a UV/IR blocking filter specifically made for the purpose of direct sunlight viewing. If you use liveview then the sensor is exposed all the time and while your eyes will be safe unless you have a very dense filter you run a fair risk of damaging the sensor.

Just checking the EXIF on a partial eclipse photo I took at f/11 with such a filter I calculated shutter speed would have had to have been about 1/500,000 without the filter, so depending on the phase of the eclipse and time of day I think often getting a properly exposed shot without some sort of filter would be impossible.

During the totality of the eclipse when it's quite dark I think you'd be safe without the filter, naked eye viewing is considered safe during that period. Personally I'd still just use liveview in that stage though in case it's over a bit quicker than you expect plus you are magnifying it a lot. NASA has a stack of information on their web site about just about all aspects including safe photography / viewing:

In addition to what PeterJ said, note that this eclipse on May 20 is annular, not total. It makes a huge difference, as the sun will never be completely covered. The eclipse in Australia later this year will be total.

I'm heading to Albuquerque to be in the center of the annular eclipse path... the forecasted sky cover is higher than I would like (27%) but I'll take my chances. I'll be using two stacked ND filters with a combined optical density of 3.9 (which according to one person at the discussion above is a recipe for disaster, but I beg to differ as I will only be using Live View and quickly framing/focusing/shooting and then covering the lens otherwise). Best of luck to everyone photographing it!

I'm heading to Albuquerque to be in the center of the annular eclipse path... the forecasted sky cover is higher than I would like (27%) but I'll take my chances. I'll be using two stacked ND filters with a combined optical density of 3.9

I'm in San Francisco, where the eclipse won't be happening until late afternoon... is it still going to require 13 stops to get a good shot?

It's probably too late for this time but the best way to find out would have been to try a few shots in the days leading up around the same time. You might be OK with less but you could well need to stop down the lens a lot more than you'd normally like to.

I'm glad I bought the proper filter, assuming you're looking for a telephoto shot I found 400mm on a crop to be quite tricky to frame so it was a big bonus being able to use LV continuously to make small adjustments, I didn't record any exact times but I seem to remember about 5 minutes was enough time for the sun to drift from center frame to towards the edge.

In Albuquerque it was really interesting because the eclipse was still happening during sunset. Because of that, the sun set in a shark fin shape. We were about a mile away from the center path of the annular eclipse, so we were able to get the moon centered nicely in the sun. There was cloud cover earlier in the day but it all went away for the eclipse... we couldn't have asked for better viewing conditions. For these photos I used a Canon Rebel T2i with a 70-200mm f/2.8L II with a 2X extender @ 400mm and two stacked neutral density filters with a combined optical density of 3.9.

In Albuquerque it was really interesting because the eclipse was still happening during sunset. Because of that, the sun set in a shark fin shape. We were about a mile away from the center path of the annular eclipse, so we were able to get the moon centered nicely in the sun. There was cloud cover earlier in the day but it all went away for the eclipse... we couldn't have asked for better viewing conditions. For these photos I used a Canon Rebel T2i with a 70-200mm f/2.8L II with a 2X extender @ 400mm and two stacked neutral density filters with a combined optical density of 3.9.

Very cool shots! Love your work.

D

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Canon 6D, 5D2, 7Dv2.03, 50D, 40D, T1i, XTi...XT (& lenses, flahses), various powershots... You get the idea... I have a problem.

Wife shoots Nikon, D7000, D7100, (lenses and flashes)... we constantly tease each other that our cameras are better than each others!

broseph

In Albuquerque it was really interesting because the eclipse was still happening during sunset. Because of that, the sun set in a shark fin shape. We were about a mile away from the center path of the annular eclipse, so we were able to get the moon centered nicely in the sun. There was cloud cover earlier in the day but it all went away for the eclipse... we couldn't have asked for better viewing conditions. For these photos I used a Canon Rebel T2i with a 70-200mm f/2.8L II with a 2X extender @ 400mm and two stacked neutral density filters with a combined optical density of 3.9.

Nice! Facebook timeline photo haha? I wish it wasn't cloudy where we were